A variety of inflatable sport balls, such as a soccer ball, conventionally exhibit a layered structure that includes a casing, an intermediate structure, and a bladder. The casing forms an exterior portion of the sport ball and is generally formed from a plurality of durable and wear-resistant panels joined together along abutting edge areas (e.g., with stitching or adhesives). Although panel configurations may vary significantly, the casing of a traditional soccer ball includes thirty-two panels, twelve of which have a pentagonal shape and twenty of which have a hexagonal shape.
The intermediate structure forms a middle portion of the sport ball and is positioned between the casing and the bladder. Among other purposes, the intermediate structure may provide a softened feel to the sport ball, impart energy return, and restrict expansion of the bladder. In some configurations, the intermediate structure or portions of the intermediate structure may be bonded, joined, or otherwise incorporated into the casing as a backing material. In other configurations, the intermediate structure or portions of the intermediate structure may be bonded, joined, or otherwise incorporated into the bladder.
The bladder, which has an inflatable configuration, is located within the intermediate structure to provide an interior portion of the sport ball. In order to facilitate inflation (i.e., with pressurized air), the bladder generally includes a valved opening that extends through each of the intermediate structure and casing, thereby being accessible from an exterior of the sport ball.
It may be desirable to provide the exterior surface of a sport ball with grooves or indentations. It may also be desirable to provide such indentations in a predetermined pattern in order to provide increased performance and to facilitate manufacturing of the ball.